Definition

1. Noun:

   • The third letter of the modern English and Roman alphabet: "C" is a consonant.
   • A musical note: In Western music, "C" is the first note of the scale of C major.
   • A grade or mark: In academic grading, "C" often represents an average or satisfactory level of achievement.
   • A Roman numeral: "C" represents the number one hundred.
   • A computer programming language: "C" is a widely used, general-purpose programming language.
   • A unit of electrical charge: The coulomb, abbreviated "C", is the standard unit of electric charge.
   • The chemical symbol for Carbon: "C" represents the element carbon on the periodic table.
   • The symbol for the speed of light: In physics, "c" denotes the constant speed of light in a vacuum.
   • A symbol for temperature: "°C" stands for degrees on the Celsius (centigrade) temperature scale.
   • A vitamin: Vitamin C, or ascorbic acid, is an essential nutrient.
   • A nucleotide base: In genetics, "C" stands for cytosine, one of the four bases in DNA and RNA.

2. Adjective:

   • Shaped like the letter C: Having a curved form similar to the capital letter C.

Usage Examples

• Noun:

  • The word "cat" begins with the letter c.
  • The song is in the key of C major.
  • She received a C on her history exam.
  • The Roman numeral C equals 100.
  • Many operating systems are written in the C programming language.
  • The charge of an electron is approximately -1.602 × 10⁻¹⁹ C.
  • Diamond is a form of the element C (carbon).
  • In Einstein's equation E=mc², c is the speed of light.
  • Water boils at 100 °C.
  • Oranges are a good source of vitamin C.
  • In a DNA sequence, C (cytosine) pairs with G (guanine).

• Adjective:

  • The dancer formed a C shape with her body.

Advanced Usage

• "C-suite": Refers collectively to a company's most important senior executives, whose titles often begin with "C" (e.g., CEO, CFO, COO).
  • Decisions about mergers are made at the C-suite level.
• "C-note": (U.S. slang) A one-hundred-dollar bill (from the Roman numeral C for 100).
  • He paid for the dinner with a C-note.

Variants and Related Words

• c.: Abbreviation for "circa" (meaning "approximately," used with dates).
  • The artifact dates from c. 1500 BCE.
• C# / C++: Object-oriented programming languages derived from C.
• c/o: Abbreviation for "care of," used when sending mail to someone at another person's address.
  • Send the package to Jane Doe, c/o John Smith.

Synonyms

• Hundred (when used as a Roman numeral).
• Satisfactory or Average (when used as a grade).
• Carbon (as a chemical element).
• Cytosine (in genetics).

Related Phrases (Phrasal Verbs)

• To get a C in (a subject): To receive a grade of C.
  • I was relieved to get a C in calculus, as it was a very difficult course.

Related Idioms

• "Straight A's and B's, no C's": An expression emphasizing high academic achievement without any average grades.
  • Her report card showed straight A's and B's, no C's.
• "Mind your P's and Q's" (Note: This is a common idiom about letters, though it uses P and Q, not C. It means to be on your best behavior).

Adjective

1. being ten more than ninety

Noun

1. street names for cocaine
2. the 3rd letter of the Roman alphabet
3. (music) the keynote of the scale of C major
4. a general-purpose programing language closely associated with the UNIX operating system
5. a unit of electrical charge equal to the amount of charge transferred by a current of 1 ampere in 1 second
6. ten 10s
7. an abundant nonmetallic tetravalent element occurring in three allotropic forms: amorphous carbon and graphite and diamond; occurs in all organic compounds
8. a base found in DNA and RNA and derived from pyrimidine; pairs with guanine
9. one of the four nucleotides used in building DNA; all four nucleotides have a common phosphate group and a sugar (ribose)
10. a vitamin found in fresh fruits (especially citrus fruits) and vegetables; prevents scurvy
11. the speed at which light travels in a vacuum; the constancy and universality of the speed of light is recognized by defining it to be exactly 299,792,458 meters per second
12. a degree on the centigrade scale of temperature